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Commit 6f86220

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Fastmode for decryption is also added.
1 parent 390170a commit 6f86220

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2 files changed

+85
-24
lines changed

2 files changed

+85
-24
lines changed

‎S_DES/DESEncryptor.go

Lines changed: 80 additions & 24 deletions
Original file line numberDiff line numberDiff line change
@@ -166,15 +166,11 @@ func (encryptor *DesEncryptor) fastEncrypt(file *os.File) {
166166
chunkMap[i] = bytesread
167167
}
168168
waitGroup.Wait()
169-
// if chunkCount == len(dataBuffer) {
170-
// fmt.Println("chunkCount and len(dataBuffer) are same")
171-
// }
172-
// Write encryption buffer into the file
169+
173170
for i := 0; i < chunkCount; i++ {
174171
encryptor.writeEncryptionBufferToFile(&encryptionBuffer[i], chunkMap[i], encryptor.encryptionFilename)
175172
}
176173
cnt += 1
177-
// fmt.Println("End of a loop, cnt:", cnt)
178174
}
179175
}
180176

@@ -227,42 +223,102 @@ func (encryptor *DesEncryptor) runEncryption(filename string) {
227223
encryptor.encryptChunk(&buffer, bytesread, &encryptionBuffer)
228224
// Write encryptionBuffer into file.
229225
encryptor.writeEncryptionBufferToFile(&encryptionBuffer, bytesread, encryptor.encryptionFilename)
230-
// fmt.Println("bytesread:", bytesread, "bytes to string:", string(buffer[:bytesread]))
231226
}
232227
normalElapsed := time.Since(normalStart)
233228
log.Println("The total time for normal mode: ", normalElapsed)
234229
}
235230
}
236231

232+
func (engine *DesEncryptor) concurrentChunkDecryption(waitGroup *sync.WaitGroup, buffer *[]byte, bufferDataSize int, decryptionBuffer *[][]byte) {
233+
defer waitGroup.Done()
234+
engine.decryptChunk(buffer, bufferDataSize, decryptionBuffer)
235+
}
236+
237+
func (engine *DesEncryptor) fastDecrypt(file *os.File) {
238+
dataBuffer := make([][]byte, engine.ConcurrentPaths) // holds the primary data to be decrypted.
239+
for i := 0; i < len(dataBuffer); i++ {
240+
dataBuffer[i] = make([]byte, engine.Chunksize)
241+
}
242+
decryptionBuffer := make([][][]byte, engine.ConcurrentPaths)
243+
for i := 0; i < len(decryptionBuffer); i++ {
244+
decryptionBuffer[i] = make([][]byte, engine.Chunksize)
245+
for j := 0; j < len(decryptionBuffer[i][j]); j++ {
246+
decryptionBuffer[i][j] = make([]byte, 8)
247+
}
248+
}
249+
waitGroup := new(sync.WaitGroup)
250+
chunkMap := make([]int, len(dataBuffer))
251+
var err error
252+
cnt := 0
253+
for err != io.EOF {
254+
err = nil
255+
bytesread := 0
256+
chunkCount := 0
257+
for i := 0; i < len(dataBuffer); i++ {
258+
bytesread, err = file.Read(dataBuffer[i])
259+
if err != nil {
260+
if err != io.EOF {
261+
log.Println("Problem reading from primary file", err)
262+
}
263+
break
264+
}
265+
waitGroup.Add(1)
266+
go engine.concurrentChunkDecryption(waitGroup, &dataBuffer[i], bytesread, &decryptionBuffer[i])
267+
chunkCount += 1
268+
chunkMap[i] = bytesread
269+
}
270+
waitGroup.Wait()
271+
272+
for i := 0; i < chunkCount; i++ {
273+
// write decryption buffer to file
274+
engine.writeDecryptionBufferToFile(&decryptionBuffer[i], chunkMap[i], engine.decryptionFilename)
275+
}
276+
cnt += 1
277+
}
278+
}
279+
237280
/**
238281
Decrypt the bytes of the encrypted file
239282
*/
240283
func (engine *DesEncryptor) runDecryption(filename string) {
241-
var buffer []byte = make([]byte, bufferSize)
242-
var decryptionBuffer [][]byte = make([][]byte, bufferSize)
243-
for i := 0; i < bufferSize; i++ {
244-
decryptionBuffer[i] = make([]byte, 8)
245-
}
246-
247-
// fmt.Println("Encryption filename:", engine.encryptionFilename)
248284
file, ferr := os.Open(engine.encryptionFilename)
285+
defer file.Close()
249286
if ferr != nil {
250287
log.Fatalln("Problem opening encrypted file...Filename:", engine.encryptionFilename, ferr)
288+
return
251289
}
252-
for {
253-
bytesread, err := file.Read(buffer)
254-
if err != nil {
255-
if err != io.EOF {
256-
log.Fatalln("Problem reading encrypted file", err)
290+
291+
if engine.Fastmode == true {
292+
log.Println("Fastmode enabled decryption...")
293+
concurrentStart := time.Now()
294+
engine.fastDecrypt(file)
295+
concurrentElapsed := time.Since(concurrentStart)
296+
log.Println("The total decryption time for fast mode: ", concurrentElapsed)
297+
} else {
298+
log.Println("Decryption in normal mode...")
299+
var buffer []byte = make([]byte, engine.Chunksize)
300+
var decryptionBuffer [][]byte = make([][]byte, engine.Chunksize)
301+
for i := 0; i < engine.Chunksize; i++ {
302+
decryptionBuffer[i] = make([]byte, 8)
303+
}
304+
normalStart := time.Now()
305+
for {
306+
bytesread, err := file.Read(buffer)
307+
if err != nil {
308+
if err != io.EOF {
309+
log.Fatalln("Problem reading encrypted file", err)
310+
}
311+
break
257312
}
258-
break
313+
engine.decryptChunk(&buffer, bytesread, &decryptionBuffer)
314+
// Write decryptionBuffer into file
315+
engine.writeDecryptionBufferToFile(&decryptionBuffer, bytesread, engine.decryptionFilename)
259316
}
260-
engine.decryptChunk(&buffer, bytesread, &decryptionBuffer)
261-
// Write decryptionBuffer into file
262-
engine.writeDecryptionBufferToFile(&decryptionBuffer, bytesread, engine.decryptionFilename)
263-
264-
// fmt.Println("Decryption, bytesread:", bytesread, " bytes to string:", string(buffer[:bytesread]))
317+
normalElapsed := time.Since(normalStart)
318+
log.Println("Total decryption time in normal mode: ", normalElapsed)
265319
}
320+
321+
// fmt.Println("Encryption filename:", engine.encryptionFilename)
266322
}
267323

268324
/**

‎des_config.json

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,5 @@
1+
{
2+
"fastmode": true,
3+
"threadcount": 8,
4+
"buffersize": 100000
5+
}

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